Web Engineering

Inlessthanadecadeofexistence,theWebhasreachedatrulystaggeringstage, demonstratedbythescope,thereach,andthesizeofWeb-basedapplications andactivities. Concentratinginitiallyoninformationdissemination,thescopeof theapplicationsisnowlimitedonlybyourimagination. Thereachisconstantly expandingandsoarethenumberandsizeoftheapplications,alongwiththe underlyingcomplexity,rangeofpurposes,andthetimeneededtodevelopand maintainthem. Atthesametime,thedevelopmentandmaintenanceprocesses ofWebapplicationshavenotprogressedatasu?cientlyrapidpacetomeetthese challengesanddemands. Consequently,thelikelihoodisthatWebapplication developmentwillgetintoacrisisanditisnothardtoimaginethatthiswould dwarfthe'softwarecrisis'identi?edlongagointhe1960s. WebEngineeringaimstoavertthispotentialcrisisbygeneratingaproactive approachtothesuccessfuldevelopmentofWeb-basedsystemsandapplications. WebEngineeringinvolvestheuseofscienti?c,engineering,andmanagement principlesandsystematicapproacheswiththeaimofsuccessfullydeveloping, deploying,andmaintaininghighqualityWeb-basedsystemsandapplications. WebEngineering,initscurrentform,isanearlyattempttoidentifythes- ni?cantissuesandproblems,andtheirsolutions,indevelopingWeb-basedapp- cations.Asweseeit,WebEngineeringisnotyetestablishedasafulldiscipline norhasitdevelopedanidenti?ableorstableform,sinceeverythingconnected withtheWebisstillinastateof?ux. Oneonlyhastolookatthenumberof variedactivitiesthattheWorldWideWebConsortiumisengagedintorealise thatastableWebenvironment,andhenceprovenmethodsfordevelopmental activitiesbasedontheWeb,isstillsomedistanceaway. OurearlyforaysintotheWebarena,withtheconstantexcitementofnew developmentsandchallenges,forcefullybroughttomindourentryintothec- puting?eld,almostthreedecadesago. Atthattime,comparedtowhatthe technologycoulddo,oure?ortsincomputerizingpayrollandaccountingapp- cationsinrealityseemedpunyanddisappointing. TheWeb,ontheotherhand, didnotseemshackled,inawaythatearlycomputingwas,tothesebure- craticandunimaginativewaysofconductinghumanandorganizationala?airs. Itseemedthattheorganizational,spatial,andphysicalconstraintswereabout toloosen,ifnotdisappear,altogether. Andyet,whenwelookedaroundatthewayWebsitesandapplicationswere beingdeveloped,itseemedtousthattheearlypatternofhaphazarddev- opment,minimaltesting,andlackofattentiontothemaintenanceissuesthat characterisedthe'softwarecrisis'werestillverymuchwithus.Itwasasthough the'newgeneration'insistedonmakingthesamemistakesasitsparents! Thisfeelingofd'ej'avuledustoquestionthenatureofWeb-basedandW- relatedactivities. Ofcourse,wewerenotalone,aswesoondiscovered. The resultiswhatisbeingcalledWebEngineeringwhichhadits?rstintroduction inaworkshopattheSeventhWorldWideWeb(WWW7)conferenceinBrisbane in1998. IthasnowbecomeaserieswithmoreworkshopsatWWW8(Toronto, VI Preface 1999)andWWW9(Amsterdam,2000),andalsoattheInternationalConference onSoftwareEngineering(ICSE99)in1999inLosAngelesandICSE2000in Limerick,Ireland. AnotherworkshopisscheduledforWWW10inHongKong inMay2001. Themainpurposebehindtheseworkshopshasbeentoshareandpoolthe collectiveexperienceofpeople,bothacademicsandpractitioners,whoare- tivelyworkingonWeb-basedsystems. Theworkshopshavegenerallyconsisted ofkeynoteaddresses,peer-reviewedcontributedpapers,andsessionsofopen discussions. About This Book Inthisvolume,weprovideaconsolidatedviewofrecentwork,highlightingdev- opmentsandadvancesintheareaofWebEngineering. Thisselectionofpapers drawsmainlyfromthelastthreeworkshops,heldinconjunctionwithICSE1999, WWW9,andICSE2000.Wealsopresentalistofadditional,usefulresourceson WebEngineeringsuchasbooks,specialissues,articles,andWebsites. Ouraim istoprovideabookthatwillbeaconvenientandusefulreferencetoallthe researchers,practitioners,andstudentsinterestedinWebapplicationdevel- ment. WebEngineeringtakesitsinspirationfromSoftwareEngineering. Atthe sametime,itisalsoanexplicitacknowledgementofthemulti-dimensionalnature ofWebapplications,encompassingtechnicalcomputing,informationstruct- ing,navigationandmanagement,networkperformanceandsecurity,legaland socialissues,graphicdesign,multiplicityofuserpro?les,andthevariedope- tionalenvironments. Accordingly,thepapersinthisvolumecoverperspectives onWebEngineering,navigationandadaptivity,designaspects,acceptancec- teriaforWeb-basedsystems,developmentandmanagementofWebsitesand Web-basedapplications,Webmetrics,andcasestudies. Forconvenience,thepapersareorganizedin?vesections:1)Introduction andPerspectives,2)ManagingInformationontheWeb,3)Web-BasedSystems Development,4)DesignforPerformance,WebMetrics,andTesting,and5) WebMaintenanceandReuse.Intheirownways,allthepapersareforwa- looking,tryingtoanticipateproblems,creatingtools,experimentinginnovel ways,wideningtheareasofapplications,andre-examiningparadigms. Inother words,thepapersrepresentasharedattitudeofbeinginclusiveratherthan focusingnarrowly. WebEngineeringisaforwardlookingandcollaborativediscipline. The- persinthiscompendium,takenindividually,representonlythetipoftheiceberg ofworldwideWebdevelopment. Together,theymakeasigni?cantcontribution totheevolutionofamoresystematicapproachtoWebdevelopment. Thec- pendiumhasbeenmadepossiblebythemanypeoplewhosharetheseviews. We hopethereaderswilljoinusintheseendeavors. January2001 SanMurugesan YogeshDeshpande Table of Contents WebEngineering:IntroductionandPerspectives WebEngineering:IntroductionandPerspectives-identi?edlongagointhe1960s. WebEngineeringaimstoavertthispotentialcrisisbygeneratingaproactive approachtothesuccessfuldevelopmentofWeb-basedsystemsandapplications. WebEngineeringinvolvestheuseofscienti?c,engineering,andmanagement principlesandsystematicapproacheswiththeaimofsuccessfullydeveloping, deploying,andmaintaininghighqualityWeb-basedsystemsandapplications.WebEngineering,initscurrentform,isanearlyattempttoidentifythes- ni?cantissuesandproblems,andtheirsolutions,indevelopingWeb-basedapp- cations. Asweseeit,WebEngineeringisnotyetestablishedasafulldiscipline norhasitdevelopedanidenti?ableorstableform,sinceeverythingconnected withtheWebisstillinastateof?ux. Oneonlyhastolookatthenumberof variedactivitiesthattheWorldWideWebConsortiumisengagedintorealise thatastableWebenvironment,andhenceprovenmethodsfordevelopmental activitiesbasedontheWeb,isstillsomedistanceaway. OurearlyforaysintotheWebarena,withtheconstantexcitementofnew developmentsandchallenges,forcefullybroughttomindourentryintothec- puting?eld,almostthreedecadesago. Atthattime,comparedtowhatthe technologycoulddo,oure?ortsincomputerizingpayrollandaccountingapp- cationsinrealityseemedpunyanddisappointing. TheWeb,ontheotherhand, didnotseemshackled,inawaythatearlycomputingwas,tothesebure- craticandunimaginativewaysofconductinghumanandorganizationala?airs. Itseemedthattheorganizational,spatial,andphysicalconstraintswereabout toloosen,ifnotdisappear,altogether.Andyet,whenwelookedaroundatthewayWebsitesandapplicationswere beingdeveloped,itseemedtousthattheearlypatternofhaphazarddev- opment,minimaltesting,andlackofattentiontothemaintenanceissuesthat characterisedthe'softwarecrisis'werestillverymuchwithus. Itwasasthough the'newgeneration'insistedonmakingthesamemistakesasitsparents! Thisfeelingofd'ej'avuledustoquestionthenatureofWeb-basedandW- relatedactivities. Ofcourse,wewerenotalone,aswesoondiscovered. The resultiswhatisbeingcalledWebEngineeringwhichhadits?rstintroduction inaworkshopattheSeventhWorldWideWeb(WWW7)conferenceinBrisbane in1998. IthasnowbecomeaserieswithmoreworkshopsatWWW8(Toronto, VI Preface 1999)andWWW9(Amsterdam,2000),andalsoattheInternationalConference onSoftwareEngineering(ICSE99)in1999inLosAngelesandICSE2000in Limerick,Ireland. AnotherworkshopisscheduledforWWW10inHongKong inMay2001. Themainpurposebehindtheseworkshopshasbeentoshareandpoolthe collectiveexperienceofpeople,bothacademicsandpractitioners,whoare- tivelyworkingonWeb-basedsystems. Theworkshopshavegenerallyconsisted ofkeynoteaddresses,peer-reviewedcontributedpapers,andsessionsofopen discussions.About This Book Inthisvolume,weprovideaconsolidatedviewofrecentwork,highlightingdev- opmentsandadvancesintheareaofWebEngineering. Thisselectionofpapers drawsmainlyfromthelastthreeworkshops,heldinconjunctionwithICSE1999, WWW9,andICSE2000. Wealsopresentalistofadditional,usefulresourceson WebEngineeringsuchasbooks,specialissues,articles,andWebsites. Ouraim istoprovideabookthatwillbeaconvenientandusefulreferencetoallthe researchers,practitioners,andstudentsinterestedinWebapplicationdevel- ment. WebEngineeringtakesitsinspirationfromSoftwareEngineering. Atthe sametime,itisalsoanexplicitacknowledgementofthemulti-dimensionalnature ofWebapplications,encompassingtechnicalcomputing,informationstruct- ing,navigationandmanagement,networkperformanceandsecurity,legaland socialissues,graphicdesign,multiplicityofuserpro?les,andthevariedope- tionalenvironments. Accordingly,thepapersinthisvolumecoverperspectives onWebEngineering,navigationandadaptivity,designaspects,acceptancec- teriaforWeb-basedsystems,developmentandmanagementofWebsitesand Web-basedapplications,Webmetrics,andcasestudies. Forconvenience,thepapersareorganizedin?vesections:1)Introduction andPerspectives,2)ManagingInformationontheWeb,3)Web-BasedSystems Development,4)DesignforPerformance,WebMetrics,andTesting,and5) WebMaintenanceandReuse.Intheirownways,allthepapersareforwa- looking,tryingtoanticipateproblems,creatingtools,experimentinginnovel ways,wideningtheareasofapplications,andre-examiningparadigms. Inother words,thepapersrepresentasharedattitudeofbeinginclusiveratherthan focusingnarrowly. WebEngineeringisaforwardlookingandcollaborativediscipline. The- persinthiscompendium,takenindividually,representonlythetipoftheiceberg ofworldwideWebdevelopment. Together,theymakeasigni?cantcontribution totheevolutionofamoresystematicapproachtoWebdevelopment. Thec- pendiumhasbeenmadepossiblebythemanypeoplewhosharetheseviews. We hopethereaderswilljoinusintheseendeavors. January2001 SanMurugesan YogeshDeshpande Table of Contents WebEngineering:IntroductionandPerspectives WebEngineering:IntroductionandPerspectives-Overview...1 WebEngineering:ANewDisciplineforDevelopment ofWeb-BasedSystems...3 SanMurugesan,YogeshDeshpande,SteveHansenandAthulaGinige WebEngineering:BeyondCS,ISandSEEvolutionary andNon-engineeringPerspectives...14 YogeshDeshpande,SanMurugesanandSteveHansen WebEngineeringinAction...24 AthulaGinige Web-BasedSystemsDevelopment:Processand Methodology Web-BasedSystemsDevelopment:ProcessandMethodology-Overview...33 CorporateWebDevelopment: FromProcessInfancytoMaturity-ACaseStudy...36 YogeshDeshpandeandAthulaGinige ApplyingCross-FunctionalEvolutionaryMethodologies toWebDevelopment...48 KennethS. Norton DevelopmentandEvolutionofWeb-Applications UsingtheWebCompositionProcessModel...58 MartinGaedkeandGuntramGraf .. EngineeringtheWebforMultimedia...77 SavithaSrinivasan,DulcePonceleon,ArnonAmir,BrianBlanchard andDragutinPetkovic ModellingSecurityPoliciesinHypermediaandWeb-BasedApplications...90 PalomaD'?az,IgnacioAedoandFivosPanetsos Web-BasedInformationSystemsDevelopment- AUserCenteredEngineeringApproach...105 ChristopheGnaho RapidServiceDevelopment:AnIntegralApproach toe-BusinessEngineering...119 WilJanssenandMaartenSteen VIII Table of Contents ManagingInformationontheWeb ManagingInformationontheWeb-identi?edlongagointhe1960s. WebEngineeringaimstoavertthispotentialcrisisbygeneratingaproactive approachtothesuccessfuldevelopmentofWeb-basedsystemsandapplications. WebEngineeringinvolvestheuseofscienti?c,engineering,andmanagement principlesandsystematicapproacheswiththeaimofsuccessfullydeveloping, deploying,andmaintaininghighqualityWeb-basedsystemsandapplications.WebEngineering,initscurrentform,isanearlyattempttoidentifythes- ni?cantissuesandproblems,andtheirsolutions,indevelopingWeb-basedapp- cations. Asweseeit,WebEngineeringisnotyetestablishedasafulldiscipline norhasitdevelopedanidenti?ableorstableform,sinceeverythingconnected withtheWebisstillinastateof?ux. Oneonlyhastolookatthenumberof variedactivitiesthattheWorldWideWebConsortiumisengagedintorealise thatastableWebenvironment,andhenceprovenmethodsfordevelopmental activitiesbasedontheWeb,isstillsomedistanceaway. OurearlyforaysintotheWebarena,withtheconstantexcitementofnew developmentsandchallenges,forcefullybroughttomindourentryintothec- puting?eld,almostthreedecadesago. Atthattime,comparedtowhatthe technologycoulddo,oure?ortsincomputerizingpayrollandaccountingapp- cationsinrealityseemedpunyanddisappointing. TheWeb,ontheotherhand, didnotseemshackled,inawaythatearlycomputingwas,tothesebure- craticandunimaginativewaysofconductinghumanandorganizationala?airs. Itseemedthattheorganizational,spatial,andphysicalconstraintswereabout toloosen,ifnotdisappear,altogether.Andyet,whenwelookedaroundatthewayWebsitesandapplicationswere beingdeveloped,itseemedtousthattheearlypatternofhaphazarddev- opment,minimaltesting,andlackofattentiontothemaintenanceissuesthat characterisedthe'softwarecrisis'werestillverymuchwithus. Itwasasthough the'newgeneration'insistedonmakingthesamemistakesasitsparents! Thisfeelingofd'ej'avuledustoquestionthenatureofWeb-basedandW- relatedactivities. Ofcourse,wewerenotalone,aswesoondiscovered. The resultiswhatisbeingcalledWebEngineeringwhichhadits?rstintroduction inaworkshopattheSeventhWorldWideWeb(WWW7)conferenceinBrisbane in1998. IthasnowbecomeaserieswithmoreworkshopsatWWW8(Toronto, VI Preface 1999)andWWW9(Amsterdam,2000),andalsoattheInternationalConference onSoftwareEngineering(ICSE99)in1999inLosAngelesandICSE2000in Limerick,Ireland. AnotherworkshopisscheduledforWWW10inHongKong inMay2001. Themainpurposebehindtheseworkshopshasbeentoshareandpoolthe collectiveexperienceofpeople,bothacademicsandpractitioners,whoare- tivelyworkingonWeb-basedsystems. Theworkshopshavegenerallyconsisted ofkeynoteaddresses,peer-reviewedcontributedpapers,andsessionsofopen discussions.About This Book Inthisvolume,weprovideaconsolidatedviewofrecentwork,highlightingdev- opmentsandadvancesintheareaofWebEngineering. Thisselectionofpapers drawsmainlyfromthelastthreeworkshops,heldinconjunctionwithICSE1999, WWW9,andICSE2000. Wealsopresentalistofadditional,usefulresourceson WebEngineeringsuchasbooks,specialissues,articles,andWebsites. Ouraim istoprovideabookthatwillbeaconvenientandusefulreferencetoallthe researchers,practitioners,andstudentsinterestedinWebapplicationdevel- ment. WebEngineeringtakesitsinspirationfromSoftwareEngineering. Atthe sametime,itisalsoanexplicitacknowledgementofthemulti-dimensionalnature ofWebapplications,encompassingtechnicalcomputing,informationstruct- ing,navigationandmanagement,networkperformanceandsecurity,legaland socialissues,graphicdesign,multiplicityofuserpro?les,andthevariedope- tionalenvironments. Accordingly,thepapersinthisvolumecoverperspectives onWebEngineering,navigationandadaptivity,designaspects,acceptancec- teriaforWeb-basedsystems,developmentandmanagementofWebsitesand Web-basedapplications,Webmetrics,andcasestudies. Forconvenience,thepapersareorganizedin?vesections:1)Introduction andPerspectives,2)ManagingInformationontheWeb,3)Web-BasedSystems Development,4)DesignforPerformance,WebMetrics,andTesting,and5) WebMaintenanceandReuse.Intheirownways,allthepapersareforwa- looking,tryingtoanticipateproblems,creatingtools,experimentinginnovel ways,wideningtheareasofapplications,andre-examiningparadigms. Inother words,thepapersrepresentasharedattitudeofbeinginclusiveratherthan focusingnarrowly. WebEngineeringisaforwardlookingandcollaborativediscipline. The- persinthiscompendium,takenindividually,representonlythetipoftheiceberg ofworldwideWebdevelopment. Together,theymakeasigni?cantcontribution totheevolutionofamoresystematicapproachtoWebdevelopment. Thec- pendiumhasbeenmadepossiblebythemanypeoplewhosharetheseviews. We hopethereaderswilljoinusintheseendeavors. January2001 SanMurugesan YogeshDeshpande Table of Contents WebEngineering:IntroductionandPerspectives WebEngineering:IntroductionandPerspectives-Overview...1 WebEngineering:ANewDisciplineforDevelopment ofWeb-BasedSystems...3 SanMurugesan,YogeshDeshpande,SteveHansenandAthulaGinige WebEngineering:BeyondCS,ISandSEEvolutionary andNon-engineeringPerspectives...14 YogeshDeshpande,SanMurugesanandSteveHansen WebEngineeringinAction...24 AthulaGinige Web-BasedSystemsDevelopment:Processand Methodology Web-BasedSystemsDevelopment:Process